1. Field of the Invention
The present invention relates to an organic EL display device and a method of manufacturing an organic EL display device.
2. Description of the Related Art
As a thin and lightweight light-emitting source, an organic light-emitting diode, that is, an organic EL (electro luminescent) element is attracting attention, and an image display device including a number of organic EL elements has been developed. The organic EL element has a structure in which at least one layer of organic thin film formed of an organic material is interposed between a pixel electrode and a counter electrode.
An organic EL display device having organic EL elements includes, for example, an element substrate having the organic EL elements arranged in a matrix corresponding to pixels and a counter substrate provided so as to face the element substrate. On such a counter substrate, color filters arranged in a matrix corresponding to the pixels and the like are formed. Since the organic EL display device has the configuration described above, light emitted from the organic EL element is directed from the element substrate toward the counter substrate side, transmits through the color filter, and exits to the outside. Moreover, at an outer periphery of the color filter, a black matrix is usually disposed as a light-impermeable film for preventing mixing of light emitted from the organic EL elements next to each other.
JP 2012-008200 A discloses, in a method of manufacturing a display device such as the organic EL display device described above, a method of overlaying an alignment mark disposed on one of substrates on an alignment mark disposed on the other substrate, as alignment of two substrates such as the element substrate and the counter substrate.